The invention relates generally to power-driven conveyors and more particularly to conveyor belts driven by one or more intermediate drive belts.
Intermediate drive belts are often used to drive conveyor belts on long or winding conveyor paths. These intermediate drive belts are short belts with drive teeth that engage the conveyor belt at strategic locations along the conveying path. In this way, part of the load is transferred from the main drive sprockets, which are typically located at the end of the conveyor carryway or in the return, to the intermediate drive belt. Because the maximum tension in a conveyor belt with intermediate drives is lower than in a conveyor belt without, a less expensive conveyor belt with a lower belt-pull rating can be used or the conveyor belt can be used for longer runs.
Some of the problems associated with conventional intermediate drive belts include: excessive wear caused by rubbing between the intermediate-drive teeth and cam surfaces acted on by the teeth; tenting of the intermediate drive belt where it engages the conveyor belt; and the need for hold downs to counteract the tendency of the intermediate drive to push the conveyor belt upward. And many intermediate drive belts and chains have pivotable teeth with cam followers that slide or roll on cam surfaces as the teeth drive the conveyor belt. Sliding cam followers are especially susceptible to wear, and rolling cam followers require more complicated roller assemblies.